As data-intensive electronic devices and applications proliferate, data rates continue to increase. In many applications, integrated circuit devices are able to function at sufficiently high data rates, but copper wire used to connect such devices to each other or to system backplanes has become a bottleneck to those data rates. For example, devices may be capable of operating internally at rates at or exceeding 10 Gbps, but external bottlenecks are caused by signal frequency-dependent loss and reflections at the backplane level, which may cause severe inter-symbol interference (ISI).
Optical signaling is one alternative that supports higher data rates because the loss of optical fiber may be “virtually” zero compared with copper. However, conversion from on-device electrical or electronic signaling to off-device optical signaling presents its own challenges. This is particularly the case where the integrated circuit device is programmable, such as, e.g., a field-programmable gate array (FPGA) or other programmable logic device (PLD). This is because the very nature of a PLD is to provide flexibility to the user (i.e., to the manufacturer of a product who incorporates PLDs into the product). Therefore, the particular type of optical-electronic interface needed will not be known by the PLD manufacturer, nor will the location on the PLD of the particular input/output (I/O) circuits to which an optical-electronic interface will need to be connected be known to the PLD manufacturer.